Ratchet jack



' pri 21,1925.

F. H. SCHWERIN RATCHET JACK Filed March 5, 1924 5 Sheets-Sheet 1 A TTORNEY F. H. SCHWE'RIN April 21, 1925.

RATCHET JACK.

File Ma h 5, "1924 a Sheets-Sheet 2 hu .nm N

Apri l 2l, 1925.

F, H. SCHWERIN RATCHET J ACK Filed March 5, 1924 3 Sheets-Sheet 5 v ATTORNEY Patented Apr. 21, 1925.

UNITED STATES PATENT OFFICE.

FRANK H. SOHVJERIN, OF WEST VIEWV, PENNSYLVANIA, ASSIGNOR TO THE DUFF MANUFACTURING COMPANY, 015 OF PENNSYLVANIA.

PITTSBURGH, PENNSYLVANIA, A CORPORATION RATCHE'I' JACK.

Application filed March 3, 1924.

To (ZZZ whom it may concern:

Be it known that I, FRANK H. SoHwnRIN, a citizen of the United States, and a resident of lVest View, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Ratchet Jack, of which the following is a specification.

The invention is an improvement in ratchet jacks and more particularly, though not exclusively, in double-acting jacks which can be either lowered by reversing the action, or tripped to drop freely. The invention comprises an improvement in the lowering device, in the trip, and in the construction, combination and sub-combinations of the whole. The general objects have been to improve such jacks in respect to increased strength with lightness, fewness of parts, increased lifting capacity, reliability, and ease of tripping.

In the accompanying drawings, illustrating the preferred embodiment of the invention:

Fig. 1 is a side elevation of the jack set for raising the load, the operating lever being shown in its lowest position;

Fig. 2 is a fragmentary side elevation, with portions broken away and in section, showing the operating lever in its lowest position and the long pawl held away from the rack by the lowering block when the mechanism is set for lowering;

Fig. 3 is a similar view more largely in section, showing the operating lever in its uppermost position, with the short pawl held away from the rack by the lowering block when the mechanism is set for lowering;

Fig. 4 is a rear to Fig. 1; and

Fig. 5 is a side elevation, with portions broken away and in section, showing both pawls clear of the rack after tripping the jack.

The jack frame is marked 1, and 2 is the toothed rack-bar guided therein and having the head 3. The operating socket lever 4 is fulcrumed in the frame at 5, and carries short and long pawls 6 and 7, which are pivoted to the lever at 8 and S) at opposite sides of the central vertical axial plane of the main fulcrum. The short pawl 6 is provided at one side with a counterweight 9 projecting forwardly in a chamber of the casing at one side of the rack.

elevation corresponding Serial No. 696,410.

At the opposite side this pawl has a rear lowering projection 10, and at this side the top of the pawl is also extended laterally at 11 beyond the side of the long pawl for a purpose which will be explained. The back of the short pawl is adapted to press against the front of the long pawl for tripping, as seen in Fig. 5. The long pawl also has a lateral lowering projection 12.

The projections and 12' ofthe pawls coact with suitable cam regions 13 and 14 on the upper edge of a lowering block is pivoted at 16 to a lugl'l' of the frame rearwardly of and above the fulcrum of the operating lever, and the block is arched so as to extend forward over the fulcrum at one side of the two pawls. The forwardly and downwardly presented nose 18 of the lowering block, lying substantially in frontofthe fulcrum, is preferably notched as indicated for guided engageme-nt with a spring 19, which is 'preferably mounted on the frame. Inthe particular construction illustrated the spring has a coil 20 about a stud 21 on the frame, an arm 22 bearing against the frame, and the projecting arm marked 19, the end of this arm being curved as shown at 23 to form a locking terminal. The block 15 has a. lateral handle projection 24, accessible in an opening in the frame, and by this handle the block can be shifted upwardly and downwardly 011 its pivot 16. In the upper oractive position of the block its cams l3 and M are yieldingly sustained by thes pring 19 in the paths of downward movement of the projections 10 and 12 of the pawls. The result is, as will be apparent from Figs. 2 and 3, that each pawl, as the pawls alternately move downward, encounters the corresponding portion of the block and downward against the resistance of the spring, until such time as the other pawl takes hold on the rack and relieves the first pawl of the load, whereupon the spring urges the block to throw thatpawl away from the rack, this action being repeated in alternation with respect to both the pawls. When the pawls alternately move upwardly they move far enough up with reference to the block to drop into engagement with the rack. hen the block is manually shifted downwardly, it is carried out of action by riding off the end of the spring. The block would then remain down out of action by lowering block 15. This forces the block virtue of gravity, but for further security it is preferably locked by the rounded terminal 23 rising in front of the nose of the block, so that the block is then non-positively locked in its down position between the end of the spring and the fulcrum boss 25 of the frame.

It will thus be seen that the lowering clevice which has been described is an improvement upon and simplification over those constructions in which the spring always tends to urge the lowering block into action, the block being positively locked out of action against this resistance of the spring by mechanical means such as a turn-button or otherwise. According to the present principle, the specific embodiment of which may be varied, the lowering block' is manually shifted in both directions into and out of a position where the spring, reacting between the block'and the frame, will produce the desired action upon the pawls. When the block is manually shifted out of action, the spring action is changed so that the spring no longer seeks to press the block into the paths of the pawls.

The novel trip of the invention is a piece 26 hung in the frame at one side of the rack to overlap the lateral extension 11 of the short pawl. The trip inclines downwardly and rearwardly from its region of swinging engagement with the frame, and tends in some degree to keep the short pawl to the rack. In former jacks a trip has been pivoted upon the short pawl, and when not in action has hung down at the back so that its weight detracted in some degree from the effect of the counterweight of the pawl. In the present construction the trip, in so far as it has any biasing effect upon the short pawl, acts with, rather than against, the counterweight. The forward upper end of the trip has a lateral pin 2'7, which is guided in an angular or curved slot 28 in the frame.

A finger knob 29 projects laterally from the trip in the side opening of the frame and enables the trip to be easily shifted from the position shown in Figs. 1 to 3, where it rides idly upon the top of the pawl 11, to the upper forward position of Fig. 5, where its notched lower end 30 will be engaged by the pawl extension 11 on the next upward movement of the short pawl so as to cause this pawl to swing rearwardly away from the rack against the long pawl, which is thereby also carried away from the rack, permitting the latter to drop. In this operation the rounded heel 31 of the trip fulcrums in a corner of the chamber of the frame. The guide 28 is preferably of angular or curved form so that its upper and forwardly directed portion 32 will afford a rest for the pin 27 of the trip, so that when the trip is shifted upwardly it weenie need not be held by the hand until the short pawl has taken hold of the notch 30. For better effect there may be a slight rise 33 at the bottom of the entrance to the rest limb of the slot.

While I have described the preferred and complete embodiment of the invention in detail, I wish it to be understood that I do not limit myself to the precise construction and that there may be various changes, substitutions, rearrangements and omissions without departing from the essential novelty.

What I claim as new is:

1. In a jack, the combination with a frame, a ratchet bar, an operating lever, and two pawls pivoted to the operating lever to work up and down reversely to each other, of a manually shiftable lowering block pivoted on the frame having portions to be encountered by the two pawls when they alternately move downward so that each pawl in turn will swing the block downward, a spring mounted on the frame and extending under the lowering block to press the same upward, said lowering block being adapted to be pushed downward manually oil the end of the spring to lie in an inactive position, and a locking terminal on the spring adapted to then rise in front of the block and lock it in its down position.

2. In a jack, the combination with a frame, a ratchet bar, a main fulcrum in the frame, an operating lever working on said fulcrum, and two pawls pivoted to said lever to work up and down reversely to each other, of a lowering block pivoted to the frame above and to the rear of the main fulcrum and extending forward over the main fulcrum toward the ratchet bar so as to swing up and down and having spaced cam projections on its upper side adapted to be encountered by the respective pawls as they alternately move downward, each iawl in turn swinging the block down, a spring mounted in the frame to extend rearward under the lowering block so as to press the same upward, said lowering block being adapted to be pushed downward manually off the end of the spring, and the spring having a rounded locking terminal which then rises in front'of the block.

3. In a double-acting ratchet jack having a frame, a rack, an operating lever and two pawls pivoted to the operating lever, a trip hung on the frame to overlie one of the pawls the trip being shiftable on the frame to a position in which it will be engaged by said pawl so as to cause both pawls to be swung away from the rack.

4. In a ratchet trip jack, the combination with a frame, a rack, an operating lever, and a pawl pivoted on the lever, of a trip hung on the frame and arranged to lie on said pawl so as to tend to keep the same to the rack, said trip being shiftable on the frame to a position in which it will'be engaged by the pawl for the purpose of dropping the rack. v

5. In a double-acting ratchet jack having a frame, a rack, an operating lever and two pawls pivoted to the operating lever, the frame having a guide, a swinging trip on the frame lying over one of the pawls and having its fulcrum portion shiftable upward along said guide to a position in which the trip will fulcrum on the frame, the trip being then in position to be engaged by the pawl to carry it away from the rack.

6. In a double-acting ratchet jack having a frame, a rack, an operating lever and two pawls pivoted to the operating lever, the frame having a guide at one side of the rack, said guide having an upper rest region, and a trip hung in the guide to lie over one of the pawls and shiftable upward to said rest region where it will fulcrum on the frame to cause said pawl to swing away from the rack against the other pawl.

7. A double-acting ratchet trip jack, having a frame, a rack, an operating lever, long and short pawls pivotedto the lever, and a trip hung on the frame at one side of the pawls, the short pawl having a lateral extension beyond the long pawl to cooperate with the trip so as to be swung away from the rack against the long pawl.

8. In a double-acting automatic lowering and trip jack, a frame, a rack, an operating lever, long and short pawls pivoted to the lever, a spring-actuated shiftable lowering block on the frame below and a shiftable trip hung on the frame above atone side of the pawls, the two pawls having lateral shoulders to act upon the lowering block, the short pawl also having a lateral extension of its top to engage said tri FRANK H. SCH'WERIN. 

